Heart scans only useful in prescribing statins under certain conditions

Date:

March 13, 2014

Source:

University of California, San Francisco (UCSF)

Summary:

As long as inexpensive statins, which lower cholesterol, are readily available and patients don’t mind taking them, it doesn’t make sense to do a heart scan to measure how much plaque has built up in a patient’s coronary arteries before prescribing the pills, according to a new study. The result is somewhat surprising, given all the evidence that has accumulated over the last decade that the test strongly predicts heart attacks, said the lead author.

Share:

Total shares:

FULL STORY

As long as inexpensive statins, which lower cholesterol, are readily available and patients don't mind taking them, it doesn't make sense to do a heart scan to measure how much plaque has built up in a patient's coronary arteries before prescribing the pills, according to a new study by researchers at UC San Francisco.

The researchers created a statistical model to predict whether or not it made sense to do the scan, using data from the Multi-Ethnic Study of Atherosclerosis and other sources. They modeled the effects of statin treatment in 10,000 55-year-old women with high cholesterol and a 10-year risk of coronary heart disease of 7.5 percent. The model predicted that giving statins to all of them would prevent 32 heart attacks, cause 70 cases of statin-induced muscle disease and add 1,108 years to their cumulative life expectancy.

Then, they looked at how a coronary artery calcium test, or CAC test, could be used to target statin therapy only to those women who the CAC test showed were at heightened risk of coronary heart disease. They found that this strategy would save money on statin costs and expose fewer women to side effects from statins but would not prevent as many heart attacks. Moreover, the test itself exposes the women to a small risk of radiation-induced cancer and costs about $200 to $400 per scan.

The researchers concluded that as long as the price of a statin remained low -- 13 cents a pill -- and did not reduce quality of life for patients, it was not cost-effective to perform a CAC test to target the drug therapy only toward those at increased risk of coronary heart disease. But if the price of the pill were more expensive -- $1 or more -- or if taking them reduced patients' quality of life, then it did make sense to use the CAC test.

The result is somewhat surprising, given all the evidence that has accumulated over the last decade that the test strongly predicts heart attacks, said the lead author, Mark Pletcher, MD, MPH, an associate professor of epidemiology and biostatistics, and medicine, at UCSF. The study was published online Tuesday, March 11, 2014, in Circulation: Cardiovascular Quality Outcomes.

Traditional prediction models, such as the Framingham-based risk equations, work imperfectly, and doctors have long sought better ways to figure out which patients would benefit most from taking statins, which can cause side effects, such as muscle aches, decreased cognitive function and cataracts.

"The prevailing wisdom is that if you have a test that predicts heart attacks, you should use it," Pletcher said. "But even a test that is strongly predictive of future events, like a coronary artery calcium scan, does not itself improve outcomes. If it is used to keep some people off of statins that would otherwise take them, then fewer people will get protection from using statins, and more people will have heart attacks."

The study incorporated data from MESA and many other sources to create a cost-effectiveness model. The researchers tested whether changing the other model inputs made a difference, and it turned out that the only critical factors were the cost of statins and the degree to which they decreased quality of life for patients.

University of California, San Francisco (UCSF). "Heart scans only useful in prescribing statins under certain conditions." ScienceDaily. ScienceDaily, 13 March 2014. <www.sciencedaily.com/releases/2014/03/140313092049.htm>.

University of California, San Francisco (UCSF). (2014, March 13). Heart scans only useful in prescribing statins under certain conditions. ScienceDaily. Retrieved August 2, 2015 from www.sciencedaily.com/releases/2014/03/140313092049.htm

University of California, San Francisco (UCSF). "Heart scans only useful in prescribing statins under certain conditions." ScienceDaily. www.sciencedaily.com/releases/2014/03/140313092049.htm (accessed August 2, 2015).

July 31, 2015  School is just around the corner, which means backpacks and packed lunches await your children. One expert offers tips for parents to promote healthy dental habits while away from ... read more

July 29, 2015  By blocking the expression of a certain gene in patients, researchers have contributed to the demonstration of great decreases in the concentration of triglycerides in their ... read more

July 29, 2015  Viewing aquarium displays led to noticeable reductions in blood pressure and heart rate, a research team found in the first study of its kind. They also noted that higher numbers of fish helped to ... read more

Mar. 17, 2015  Hormones may not protect women from heart disease or stroke after menopause, but when combined with cholesterol-lowering statin drugs, they may help protect women from these killers, shows a ... read more

Aug. 14, 2014  A Mayo Clinic task force challenges some recommendations in the updated guideline for cholesterol treatment unveiled by the American College of Cardiology (ACC) and American Heart Association (AHA) ... read more

Feb. 4, 2014  Clinicians and patients should use shared decision-making to select individualized treatments based on the new guidelines to prevent cardiovascular disease, according to a new commentary by ... read more

Nov. 18, 2013  Children with inherited high levels of cholesterol who receive cholesterol-lowering statins in their early years have a lower risk of coronary heart disease than their affected parents, according to ... read more